Diagnostic Testing

The first step in helping your child is to determine, as precisely as possible, the location and cause of the seizures. The epilepsy surgery team’s evaluations use the most advanced diagnostic methods available, some of which are offered only through our program.

This section describes specifics of the tests we use. Each test provides us with additional information to help pinpoint the source and cause of your child’s seizures.

Video electroencephalogram (VEEG) is a painless, noninvasive test that records the electrical activity in your child’s brain by means of electrodes attached to the scalp. VEEG allows the doctor to see how your child’s behavior during seizures is related to the brain’s electrical activity. With VEEG, your child is videotaped while his EEG is recorded. We perform this test for 24 hours, up to five days, in your child’s hospital room. In some cases, your child may have to return for an additional hospital stay if we need to gather more information.

Preparing Your Child for the EEG TestBring all medicines your child is taking, both prescription and non-prescription, in their original containers. Wash your child’s hair the night or morning before the test. Your child’s hair must be clean and dry and you should not put any special conditioners, oils or hair spray on your child’s hair. Bring comfortable clothing, and shirts should button up the front. Since your child will stay for at least 24 hours, the accommodations are large enough for two adults to stay overnight. Patients must have a parent or guardian stay with them during the entire hospital stay. We recommend that you bring extra clothing, slippers, underwear, a hairbrush, toothbrush and toothpaste, deodorant, shampoo and things to keep your child busy such as books, magazines, games, CD players, VCR tapes, DVDs, laptop computers and schoolwork.

What to Expect During the TestFor the EEG test, your child may need an intravenous line (IV), a tube inserted in the arm with a needle and used to administer medications. The EEG technologist will use a special glue to apply the electrodes (the devices that transmit the brain’s electrical impulses) to your child’s scalp. The glue has a strong odor, but is not harmful. To help the glue dry, the technologist will blow air onto the electrode. We will place a special cap on your child’s head, over the electrodes. We will check the electrodes regularly, and if any electrodes are not recording EEG activity, we will reattach them. The technologist will remove the electrodes on the day your child is to go home. Do not remove the electrodes yourself, or allow your child to remove them.

MRI uses large magnets, radio waves and a computer to make detailed pictures of organs and structures inside the body. MRI helps determine if there is an irregularity in your child’s brain such as tissue scarring, a malformation, infection or tumor that is causing seizures. Your child may have had an MRI previously, but this test will be repeated for evaluations. The 3T MRI test has higher resolutions so it can offer greater detail of the brain’s structures.

Preparing Your Child for the MRI ProcedureBecause the MRI creates a strong magnetic field, you must remove any of your child’s jewelry or other metal objects, such as barrettes, eyeglasses, dental pieces or hearing aids. If your child has any health-related metal devices (pacemakers, metal plates, vagal nerve stimulators (VNS), braces), contact the lab at 513-636-0332. Let us know in advance if she has any type of medication patch because it can cause burns if worn during the MRI procedure.

What to Expect During the MRI ProcedureDuring the procedure, it is important that your child lie very still. We may give your child a light sedative if he is unable to lie still on his own. The sedative may be given intravenously (through a needle inserted in the arm), or we may give it by mouth. The MRI staff will be in another room where the scanner controls are located. The staff can talk with your child through a speaker and hear what she says. The technologist will be watching your child at all times and will be in frequent communication. The MRI is usually less than an hour in length.

Single photon emission computed tomography (SPECT) is a test to show areas of increased brain activity related to blood flow. It helps pinpoint the area causing seizures by showing where there is increased blood flow in the brain. There are two kinds of SPECT scans:

Ictal SPECT: a procedure done while a seizure is occurring

Inter-ictal SPECT: a procedure done between seizures

Preparing Your Child for the SPECT ProcedureYour child can eat or drink as usual before the procedure. There are no special preparations needed, unless your child needs sedation. We will notify you ahead of time if this is necessary.

What to Expect During the SPECT ProcedureAt your child’s bedside, we will inject a small amount of a medication, called an isotope, through an intravenous (IV) line into his vein. The isotope is carried to the brain through the bloodstream and will last for six hours. It does not cause seizures. It travels to the place in the brain where there is greatest blood flow, which may be the location of the seizure. For an ictal SPECT, we inject the isotope during a seizure. For an inter-ictal SPECT, we inject the isotope between seizures; this can be done during an outpatient visit. After injection, your child will lie flat on a special table that will slide into the scanner. A special head rest will be used to hold your child’s head still. There is no pain during the test and it usually lasts 30-45 minutes.

About Subtraction Ictal SPECT Co-Registered to MRI (SISCOM)Through SISCOM, the ictal and inter-ictal SPECT scans and the MRI’s images are compared and developed into a three-dimensional brain image. This image highlights the areas of increased blood flow, thus helping determine the area of seizure focus. SISCOM is an important process that helps locate the focus of seizure activity.

Positron emission tomography (PET) is a type of test that measures metabolic activity within the brain cells. PET helps us see the biochemical changes taking place in the brain that can cause seizures. If an area of the brain is using less glucose, or blood sugar, that may help to determine where there is seizure activity.

What to Expect During the PET ProcedureYour child may not eat or drink for four hours before the test. During the test, your child will lie on a table that slides into the PET scanner. It is important for your child to lie quietly, so we may give her a sedative to help stay still. We will place a small amount of glucose-based material into your child’s vein through an intravenous (IV) line. If your child is a patient in the hospital, this IV will already be in place. If your child has the test as an outpatient, the IV will be placed in his arm. The scan causes no pain or discomfort. The scanner maps the image of the area, allowing the doctor to see where cell activity is taking place. Decreased cell activity or “cold spots” identify possible areas of seizure activity. The test will last one hour.

Magnetoencephalography (MEG) is a test that records brain activity. It is one of the newest, non-invasive tests available for studying epilepsy and brain function. It measures small magnetic fields produced by discrete electrical currents starting inside the neurons of the brain. MEG is similar to electroencephalography (EEG), but with less effect on the skull and tissues surrounding the brain by the magnetic fields, a more accurate and less distorted image can be created regarding the brain’s electrical activity. When a patient is being considered for surgery, MEG provides accurate, reliable information about where motor, sensory and language areas are in the brain and where seizures occur.

Preparing Your Child for the MEGIf your child takes medication for epilepsy, have her take the medication as normal before the test. For the test, make sure your child does not wear any metal objects such as watches, necklaces or earrings. He should also not have on any medication patches. If possible, have your child wear clothing for the test that contains no metal snaps or zippers. If your child has any health-related metal devices (pacemakers, metal plates, vagal nerve stimulator, braces), contact the MEG lab at 513-636-0332. If your child is having the MEG test as an outpatient and will need sedation for the procedure, a representative from our same day surgery area will call you the day before with eating guidelines and instructions for when and where to arrive.

What to Expect During the MEG ProcedureYour child will lie down, and need to be still, on a table in a quiet room on A-7. If she is unable to lie still on her own, she may be given a light sedative by mouth. We will first test your child during drowsiness or sleep. During this time, we apply a small electrical stimulation at the wrist to localize the sensory area in the brain. Your child might continue sleeping during this part of the test. We will then test your child while he is awake, performing tasks like reading, looking at pictures, or pressing buttons. The test can last 1½ hours to four hours, depending on how much information is needed.

The neuropsychological evaluation tests abilities such as language, visual-spatial skills, memory, problem-solving, motor skills and behavioral functioning. The tests are given by neuropsychologists and technicians. They are not invasive. Depending on your child’s age and ability, the evaluation lasts two to six hours. If your child has had a neuropsychological evaluation or intellectual / academic testing at school in the past, it is important to provide those results to the neuropsychologist for comparison. The neuropsychologist will notify your child’s pediatrician, epileptologist and neurologist of the testing results. In addition, the specifics will be reviewed with you in detail, with possible recommendations for additional therapies (speech, PT or OT), behavioral treatment or modifications to your child’s academic program.

The Wada test comes from the physician, Juhn Wada, who first performed it. It uses a type of X-ray to identify which side of your child’s brain is essential for language function. It may also provide some information about memory. This test is used only when your child’s seizures may be in an area of the brain affecting speech, language and memory. It is important to make sure these important human functions are not altered by any surgery performed. Your child will be awake during the test so he may follow simple instructions and answer questions.

Preparing Your Child for the Wada TestBefore the Wada test, the doctor will explain the procedure to you and your child. Your child must be old enough and able to follow simple instructions and to lie still for approximately an hour during the test. We will perform blood tests before the procedure that tell us how quickly your child’s blood clots. Let your doctor know:

If your child is taking any medications that may affect her blood’s ability to clot, or if he has a bleeding disorder

If your child has an allergy to iodine or contrast material (“dye”)

If your child has diabetes

If she has a history of kidney disease

Do not give your child anything to eat or drink after midnight the evening before the test. However, your child should take his regular seizure medicine as scheduled, with as little water as possible.

What to Expect During the Wada TestYour child will be awake and lying down for both parts of the Wada test. The first part is an angiogram, a test that looks at blood flow in the brain, to make sure there are no obstacles to performing the test. We will inject a numbing medicine into her upper leg, where the doctor will make a small incision and insert a thin catheter (tube). The doctor advances the tube through an artery in the leg, then injects a liquid contrast material, or dye, into the tube. The dye enters the blood vessels and is viewed on an X-ray machine as it passes to the brain. The purpose of this part of the test is to observe how blood flows to the brain. Your child will be asked to answer some simple questions and to perform a few basic tasks during the test.

In the second part of the Wada test, we inject a medicine into the catheter. The medicine puts each half of the brain to sleep in turn, while your child is asked questions to test his language and memory. This medication might make your child feel sleepy and unable to move one side of his body. This is temporary, and will only last three to five minutes. Once testing is complete and the medicine has worn off (in fewer than 30 minutes), we test the opposite side of the brain. After both sides are tested, we remove the catheter and put pressure on the entry site for 10 to 15 minutes to prevent bleeding. A regular bandage is all that is needed for the site where the incision was made.

After the Wada TestWe will take your child to a hospital room for observation for eight hours, where you may stay with him. Your child must lie flat for four hours to make sure the incision in the thigh clots and that there is no bleeding. Your child may return home the same day. Your child may shower and resume normal activity 24 hours after the procedure. She should avoid sitting longer than three hours at a time for the first two days after the procedure to aid in the healing of the incision site. For five days after the test, your child should not soak in a tub or go swimming, lift anything heavier than 10 pounds or perform any strenuous activity such as sports or mowing the lawn.